The subtangent, ordinate and subnormal to the parabola $y^2=4ax$ at a point (different from the origin) are in:

G.P.

$\frac{d}{dx}(y^2)=\frac{d}{dx}(4ax)⇒\frac{dy}{dx}=\frac{2a}{y}$

At (x, y), subtangent = y²/2a, ordinate = y, Subnormal = 2a

(Important : These are in G.P. (For any curve, subtangent, ordinate, subnormal are in (G.P.))